Have 5 days to spend between HCM City and Taipei. Will have stayed at Phu Quoc island for a couple of days before departing from the area. Any suggestions on where I should travel to before departing home from Taipei?
In terms of flights, Hong Kong would be a convenient stop in between Saigon and Taipei. You should be able to get direct flights from Saigon to Hong Kong, then from Hong Kong to Taipei. There is more than enough in Hong Kong (and nearby Macau) to keep you busy for 5 days.
Hong Kong would indeed be a great choice. Would also suggest Singapore if you've not already been there.